June 16, 2013
Sugar Can Stress Out Your Heart
Brett Smith for redOrbit.com - Your Universe Online
“When the heart muscle is already stressed from high blood pressure or other diseases, and then takes in too much glucose, it adds insult to injury,” said study co-author Dr. Heinrich Taegtmeyer, a medical school professor of cardiology at the University of Texas Health Science Center at Houston.
According to the study, the glucose metabolite molecule, glucose 6-phosphate (G6P), can cause stress to the heart — changing muscle proteins and disrupting heart pump function in a way that leads to heart failure.
To reach their conclusion, Taegtmeyer and colleagues performed several experiments on rat hearts, ex vivo, or outside the rat´s body. Experiments were performed this way to “elucidate the mechanisms” suggested by previous research and to allow for more control over conditions, the study said.
The research team also performed tests on deficient heart tissue taken from eleven patients at the Texas Heart Institute who had the heart muscle removed in the process of corrective surgery. Using biochemical and genetic analyses, both sets of experiments led to uncovering the damage caused by G6P.
Taegtmeyer noted the study´s findings could have significant ramifications for the prevention of heart failure, a disease with a post-diagnosis survival rate of 50 percent that impacts 5 million Americans a year, according to the Centers for Disease Control.
“Treatment is difficult,” Taegtmeyer said. “Physicians can give diuretics to control the fluid, and beta-blockers and ACE inhibitors to lower the stress on the heart and allow it to pump more economically.”
“But we still have these terrible statistics and no new treatment for the past 20 years,” he added.
According to a statement from the American Heart Association, the study has already led to potential new treatments. Rapamycin, an immunosuppressant, and metformin, a diabetes medication, have been found to disrupt the signaling of G6P and boost cardiac power in small animal studies.
“These drugs have a potential for treatment and this has now cleared a path to future studies with patients,” Taegtmeyer said.
Heart failure, marked by the ineffective pumping of blood, can be caused by heart attack, diabetes, high blood pressure and viral infections. The AHA study comes just after a team of California-based researchers published a study showing the progress made by newer treatments for the disease.
Medical advancements over the past 20 years have led to a panoply of new treatment and researchers from UCLA decided to look into their effectiveness.
The study included 2,500 patients who had been treated at a UCLA medical facility from 1993 to 2010. Three drug-based treatments, (ACE inhibitors, beta blockers, and aldosterone antagonists), have been widely used to treat heart failure between 1993 and 2010. Meanwhile, the use of implanted automatic heart defibrillators in heart failure patients has gone from 11 percent to 68 percent. The devices correct abnormal heart rhythms, a frequent cause of sudden death.
The California researchers found death rates were 42 percent lower for patients in the most recent treatment group, between 2005 and 2010, than for the patients in the 1990s, mostly due to the drop in sudden deaths.